Hi
I was searching eBay for PCM1794, and found this nice DAC board,
which apparently is named "1794 Pro":
Assembled SA9023+PCM1794 Decoder Board DAC Kit Decoder DAC Sound Card | eBay
Does anyone know if using the "AC In" connector is mandatory,
or the board can be powered via USB without needing to add an AC Power Supply?
Thank you
I was searching eBay for PCM1794, and found this nice DAC board,
which apparently is named "1794 Pro":
Assembled SA9023+PCM1794 Decoder Board DAC Kit Decoder DAC Sound Card | eBay
Does anyone know if using the "AC In" connector is mandatory,
or the board can be powered via USB without needing to add an AC Power Supply?
Thank you
Last edited:
The board uses dual 5V AC, generating symmetric power supply. You would need a 5V -> -5V convertor for USB voltage plus USB 5V is way noisier than output of the onboard regulator.
The seller says 10W. USB port fetches by standard 5V * 500mA = 2.5W.
Now you know the answer to your question
The seller says 10W. USB port fetches by standard 5V * 500mA = 2.5W.
Now you know the answer to your question
Power wise, I'd say we're looking at well under a watt there, depending on how high the analog supplies are (presumably anywhere from +/-5 to +/- 8 V - not sure why the regulator footprints seem to be suggesting 7815 + 780x, looks like a regular split supply job to me). They're using 5532 opamps, which generally require a minimum +/-5 V supply. While a number of audio opamps will run to 5 V or even below, their voltage swing at low supplies may be less than stellar.
You could run a circuit like this from USB power, but it would require step-up converters - this board uses all conventional linear regulators.
You could run a circuit like this from USB power, but it would require step-up converters - this board uses all conventional linear regulators.
E.g. this DAC Khadas Tone Board Hi-Res Audio Development Board for Music Fanatics is a good example of symmetrical supply generation from USB (schematics included - good for inspiration) while keeping excellent params Review and Measurements of WesionTEK Khadas Tone Board DAC | Audio Science Review (ASR) Forum .
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